The fundamental processes of chemistry, biology and material science are
mediated by electronic and nuclear motions of the constituent atoms. The electronic
motions inherent to these systems have attosecond time-scales (1 attosecond = 10-18 sec)
which are too fast to resolve with current technology.

This Basic Technology project aims to develop the technological tools to study electron
motion in matter with both attosecond time-scale resolution and sub-Ångstrom spatial resolution.
Underpinned by extreme-ultraviolet (EUV) light sources producing attosecond duration light pulses,
these tools open the door not only for real-time observation but also time-domain control of electron
dynamics on the atomic scale.

Our team comprising scientists from Imperial College London, University College London,
the universities of Oxford, Reading Birmingham, and the Rutherford Appleton Laboratory (CCLRC)
has brought together a range of expertise to tackle these challenges. As we have developed the
technology, new science has followed, for example we have made the fastest ever measurement of
molecular dynamics. The project has also succeeded in training more than a dozen doctoral students
and fostering a new UK attosecond science community. It has also transferring new technology to the
UK science base thereby increasing both the expertise and the capacity to do attosecond science in the UK.

Hollow-Fibre Pulse Compressor - see Fig. 1. We have developed an optical system that compresses high power
(100GW) near IR femtosecond pulses to the “few-cycle” limit, i.e. to durations approaching 5 fs, with
carrier-envelope phase stabilisation. These pulses- amongst the shortest, highest power pulses in the
world - are used to generate attosecond EUV pulses via the process of High Harmonic Generation.

Novel pulsed-valve (Fig. 2) developed to deliver gas plumes to laser interaction experiments at kHz
repetition rates and with high backing pressures.

“Jitter-free” EUV delay stage. This highly stable piezo-actuated two-part Mo/Si mirror
allows optical and EUV (13nm) pulses to be precisely delayed with respect to each other
(<50 attsecond resolution). This is used to measure the duration of attsoecond EUV pulses.

We developed a vibration isolation technology to allow optics in vacuum beamlines to be stabilised
with interferometric stability relative to external optics. This is vital for attosecond resolution
pump-probe experiments.

Fig. 5: Experimental measurements of half-cycle cut-offs in high harmonic generation on the cover of Nature Physics.

Fig. 4: BBC website coverage of an experiment undertaken as part of the Attosecond Technology project.

Attosecond beamline at Imperial College London. This state-of-the-art vacuum beamline is used
for the generation, filtering, focusing and delivery of attosecond EUV and few-cycle near-IR pulses
in pump-probe configuration to a range of experiments (e.g. molecular physics and surface science studies).

Our beamline and laser systems technology as well as expertise is being transferred to the
Astra-Artemis Project at RAL. Due to be completed in early 2009 this user-facility will provide
few-cycle, carrier-envelope phase stablised pulses at a range of wavelength (including EUV) to
user experiments. Attosecond capability is projected after a second phase of development.

Fig. 8: Schematic of the laboratory for the Artemis project at the Rutherford Appleton Laboratory.

Training of young scientists

Centred at Imperial College London, the project has connected a number of UK universities
and institutes – in many cases creating new bridges between research areas and research groups.

PhD students connected with the project during a one-day symposium they organised in Dec 2005 at
RAL. Training of researchers has been one of the most important outcomes of the project.

An international workshop was held in April 2006 as part of this Basic Technology project.
Funded by EPSRC, the ESF and through commercial sponsorship it attracted more than 120 delegates
from the UK and overseas, including twenty field-leading invited speakers. The workshop also provided
an opportunity to showcase the UK attosecond project. Free registration was provided for all students.

Fig. 9: PhD students at a project meeting in 2005.

Fig. 10: Delegates attending the Ultrafast Dynamic Imaging Workshop, held at Imperial College London in 2006.